Is it worth it to cryopreserve embryos with blastulation delay at day 5?

Abstract

SummaryThis is a retrospective study over a 5-year period. In total, 3139 embryos were individually cryopreserved (Cryotop®) and warmed using the Kitazato vitrification/warming kit. They were classified into three categories based on their expansion degree. Transfer, implantation and pregnancy rates were assessed for each embryo category and compared using SPSS (Statistical Package for the Social Sciences) software. In total, 1139 couples enrolled in infertility treatment programme benefitted from embryo vitrification at day 5. After warming, embryos belonging to the three categories showed similar success rates. Although there was a trend towards better outcomes when grade 3 embryos were transferred, the differences did not reach statistical significance: implantation rates (n fetal sac/n embryo transferred) grade 1: 21.9%, grade 2: 22.7% and grade 3: 30.3% (=0.19). Pregnancy rate (n clinical pregnancy/n transfer) (21.9%, 22.7%, 30.3%, respectively; P=0.11). Miscarriage rate was not statistically different in the three categories (14.5%, 20.4%, 20%, respectively, P=0.51). Our overall results show that it is worth vitrifying slow kinetics embryos as they provide a non-negligible chance to give rise to a pregnancy.

Social Freezing: Pressing Pause on Fertility

“…Monjean et al showed that vitrifying slow kinetics embryos are a procedure worth envisaging as it generated a non-negligible chance of pregnancy in a five-year prospective study on individually cryopreserved (Cryotop ® ) and warmed (Kitazato vitrification/warming kit) embryos with endpoints of transfer, implantation, and pregnancy rates. The pregnancy versus transfer was as high as 30.3% in the grade-three embryos based on development [31].…”